Fourier Amplitude Spectra

02-Analytical capabilities
Post Reply
sam123
Posts: 6
Joined: 11 Nov 2017, 01:27

Fourier Amplitude Spectra

Post by sam123 » 15 Apr 2018, 23:07

Hi everyone

What procedure is used in the Seismosignal to obtain the Fourier Amplitude spectra? Please explain required steps to calculate the Fourier Amplitude spectra of an input record in this software.

Thanks so much

User avatar
z.gronti
Posts: 465
Joined: 16 Oct 2013, 08:14

Re: Fourier Amplitude Spectra

Post by z.gronti » 16 Apr 2018, 09:30

Dear sam123,

Once you load the record, the Fourier Amplitude Spectrum and the Power Spectrum are automatically computed. Please refer to "Fourier and Power Spectra" page of SeismoSignal Help System for more information.
Zoi Gronti
Seismosoft Srl.

sam123
Posts: 6
Joined: 11 Nov 2017, 01:27

Re: Fourier Amplitude Spectra

Post by sam123 » 16 Apr 2018, 15:00

Dear z.gronti

Thank you for your response but I did not find a detailed description for the calculation of the fourier amplitude spectra in the page of SeismoSignal Help System. I would be grateful if you could guide me about that how is calculated fourier amplitude spectra in the seismosignal.

User avatar
seismosoft
Posts: 608
Joined: 06 Jul 2007, 04:55

Re: Fourier Amplitude Spectra

Post by seismosoft » 18 Apr 2018, 19:50

Hello sam123,
You may find the description you are looking for in any good textbook or in the internet (e.g. see: https://en.wikipedia.org/wiki/Fast_Fourier_transform)
Seismosoft Support

antoniic
Posts: 1
Joined: 10 Dec 2018, 14:09

Re: Fourier Amplitude Spectra

Post by antoniic » 10 Dec 2018, 14:13

Hello

How could I create Fourier Amplitute Spectrum for Dispplacement, from Seismosignal.
Seismosignal create FAS only for acceleration.

Yours Faithfully

huffte
Posts: 840
Joined: 22 Jul 2011, 10:19
Location: Cookeville, Tennessee, USA
Contact:

Re: Fourier Amplitude Spectra

Post by huffte » 10 Dec 2018, 14:36

I suppose there is nothing to prevent you from saving an integrated displacement history as a text file and loading that into SeismoSignal. I am not sure what units problems you might run into., however.
Tim Huff

Navid
Posts: 17
Joined: 18 Jun 2017, 02:09

Re: Fourier Amplitude Spectra

Post by Navid » 19 Oct 2019, 10:28

Hey There. I am kinda lost. What is the unit of Fourier amplitude, calculated by SeismoSignal? My understanding is that the said unit should be g.s, meaning that Fourier amplitude times the frequency should give the corresponding value of Sa (g).

Image

User avatar
Fanis_Moschas
Posts: 5
Joined: 21 Aug 2018, 14:27

Re: Fourier Amplitude Spectra

Post by Fanis_Moschas » 22 Oct 2019, 16:03

Hello Navid,
the amplitude units are same as the units of your time series (for example g, m/sec or whatever your units are) multiplied by seconds (the time interval unt). So in order to obtain the real amplitude for a specific frequency in your results you need to multiply the amplitude with 2 (due to the two sided shape of the Fourier transform results) and then divide it by the number of points of your time series and by the time step (dt in seconds).
Best Regards
Fanis Moschas
Fanis Moschas
Seismosoft Srl.

Post Reply